sr=waterson. comment change only

xpcom/ds/nsIEnumerator.idl

@@ -27,7 +27,10 @@
 %}
 
 /**
- * nsISimpleEnumerator
+ * Used to enumerate over elements defined by its implementor.
+ * Although hasMoreElements() can be called independently of getNext(),
+ * getNext() must be pre-ceeded by a call to hasMoreElements(). There is
+ * no way to "reset" an enumerator, once you obtain one.
  *
  * @status FROZEN
  * @version 1.0
@@ -35,7 +38,34 @@
 
 [scriptable, uuid(D1899240-F9D2-11D2-BDD6-000064657374)]
 interface nsISimpleEnumerator : nsISupports {
+  /**
+   * Called to determine whether or not the enumerator has
+   * any elements that can be returned via getNext(). This method
+   * is generally used to determine whether or not to initiate or
+   * continue iteration over the enumerator, though it can be
+   * called without subsequent getNext() calls. Does not affect
+   * internal state of enumerator.
+   *
+   * @see getNext()
+   * @return PR_TRUE if there are remaining elements in the enumerator.
+   *         PR_FALSE if there are no more elements in the enumerator.
+   */                                            
   boolean hasMoreElements();
+
+  /**
+   * Called to retrieve the next element in the enumerator. The "next"
+   * element is the first element upon the first call. Must be
+   * pre-ceeded by a call to hasMoreElements() which returns PR_TRUE.
+   * This method is generally called within a loop to iterate over
+   * the elements in the enumerator.
+   *
+   * @see hasMoreElements()
+   * @return NS_OK if the call succeeded in returning a non-null
+   *               value through the out parameter.
+   *         NS_ERROR_FAILURE if there are no more elements
+   *                          to enumerate.
+   * @return the next element in the enumeration.
+   */
   nsISupports getNext();
 };